Simulation analysis of rock braking mechanism of tunnel boring machine

U svrhu odgovora na pitanja trošenja i oštećenja odvalnog glodala u postupku loma stijene, simulirao se postupak loma stijene pri raznim stanjima loma primjenom metode konačnih elemenata. Odnos između normalne sile, lateralne sile, sila pri valjanju i vremena dobiven je analizom simulacije loma stijene strojem za rezanje s jednom oštricom. Naprezanje stijene se analiziralo na različitim dubinama kad naprezanje dostigne maksimalnu tlačnu čvrstoću stijene. Najbolji prostor za rezanje postignut je na određenoj dubini analizom stanja naprezanja oštrice stroja u različitim prostorima. Učinkom oblika poprečnog presjeka oštrice na trošenje završen je ovaj rad. Istraživanje je pružilo reference vezano za trošenje i optimizirani dizajn glodala na stroju za bušenje tunela.Aiming at answering the questions of wear and failure of hob in the rock breaking process, the rock breaking process was simulated in different broken rock conditions by using finite element method. The relationship between normal force, lateral force, rolling force and time was obtained by rock breaking simulation analysis on the single edge disc cutter. The rock stress was analysed by setting different cutting depth when the stress reaches the maximum compressive strength of the rock. The best cutter space was also obtained in a certain depth by analysing the stress state of the cutter in different cutter space. The paper concluded with the effect of the disc cutter cross section shape on the wear. Therefore the study provided references for the wear and the optimized design of hob on Tunnel Boring Machine

Neutron star magnetic field evolution, crust movement and glitches

Spinning superfluid neutrons in the core of a neutron star interact strongly with co-existing superconducting protons. One consequence is that the outward(inward) motion of core superfluid neutron vortices during spin-down(up) of a neutron star may alter the core's magnetic field. Such core field changes are expected to result in movements of the stellar crust and changes in the star's surface magnetic field which reflect those in the core below. Observed magnitudes and evolution of the spin-down indices of canonical pulsars are understood as a consequence of such surface field changes. If the growing crustal strains caused by the changing core magnetic field configuration in canonical spinning-down pulsars are relaxed by large scale crust-cracking events, special properties are predicted for the resulting changes in spin-period. These agree with various glitch observations, including glitch activity, permanent shifts in spin-down rates after glitches in young pulsars, the intervals between glitches, families of glitches with different magnitudes in the same pulsar, the sharp drop in glitch intervals and magnitudes as pulsar spin-periods approach 0.7s, and the general absence of glitching beyond this period.Comment: LaTex, 28 pages, 8 figs, accepted for publication in Ap

Establishment of reference intervals for thyroid hormones in premature infants beyond the first week of life using Beckman Coulter Unicel DxI 800.

BACKGROUND(#br)This 4-year retrospective cohort study aimed to establish reference intervals for free triiodothyronine (FT3), free thyroxine (FT4), and thyrotropin (TSH) in premature infants using the Beckman Coulter Unicel DxI 800 automated immunoassay system.(#br)METHODS(#br)Study subjects included 605 preterm infants with a gestational age of 26-36 weeks (corrected: 29-38 weeks). Pearson correlation was used to evaluate the association between hormone levels and gestational and corrected gestational ages. A nonparametric method was used to establish reference intervals based on corrected gestational age.(#br)RESULTS(#br)FT3 and FT4 levels were positively correlated with gestational and corrected gestational ages, respectively. TSH levels were slightly negatively correlated with gestational and corrected gestational ages. FT3 significantly differed according to corrected gestational age (29-33 weeks vs 34-38 weeks); however, the difference was smaller than the reference change value (RCV) for the FT3 test. Thus, we combined the FT3 reference intervals into a single reference interval: 2.65-4.93 pmol/L (29-38 weeks). The reference intervals of FT4 and TSH were 11.20-24.97 pmol/L (29-38 weeks) and 1.01-10.14 mIU/L (29-38 weeks), respectively.(#br)CONCLUSIONS(#br)Unlike those of full-term infants or adults, the reference intervals established in this study are applicable in premature infants. These results highlight the importance and complexity of establishing instrument-specific thyroid hormone reference intervals for preterm infants

Establishment of reference intervals for thyroid hormones in premature infants beyond the first week of life using Beckman Coulter Unicel DxI 800

Abstract(#br)Background(#br)This 4-year retrospective cohort study aimed to establish reference intervals for free triiodothyronine (FT3), free thyroxine (FT4), and thyrotropin (TSH) in premature infants using the Beckman Coulter Unicel DxI 800 automated immunoassay system.(#br)Methods(#br)Study subjects included 605 preterm infants with a gestational age of 26–36 weeks (corrected: 29–38 weeks). Pearson correlation was used to evaluate the association between hormone levels and gestational and corrected gestational ages. A nonparametric method was used to establish reference intervals based on corrected gestational age.(#br)Results(#br)FT3 and FT4 levels were positively correlated with gestational and corrected gestational ages, respectively. TSH levels were slightly negatively correlated with gestational and corrected gestational ages. FT3 significantly differed according to corrected gestational age (29–33 weeks vs 34–38 weeks); however, the difference was smaller than the reference change value (RCV) for the FT3 test. Thus, we combined the FT3 reference intervals into a single reference interval: 2.65–4.93 pmol/L (29–38 weeks). The reference intervals of FT4 and TSH were 11.20–24.97 pmol/L (29–38 weeks) and 1.01–10.14 mIU/L (29–38 weeks), respectively.(#br)Conclusions(#br)Unlike those of full-term infants or adults, the reference intervals established in this study are applicable in premature infants. These results highlight the importance and complexity of establishing instrument-specific thyroid hormone reference intervals for preterm infants

Digital back-propagation in optical fiber communication systems considering equalization enhanced phase noise

The effect of equalization enhanced phase noise (EEPN) will be introduced in digital signal processing (DSP) based coherent optical communication systems. The EEPN will seriously degrade the transmission performance of a highcapacity optical transmission system. In this work, the influence of EEPN on the performance of dual-polarization 16-ary quadrature amplitude modulation (DP-16QAM) optical transmission system using the electrical dispersion compensation (EDC), the single-channel digital back-propagation (DBP), the partial-bandwidth DBP and the full-field DBP (FF-DBP) were comparatively evaluated with and without considering distortions from the EEPN. Deteriorations on achievable information rates (AIRs) and modulation error ratios (MERs) of optical communication systems due to EEPN have also been assessed. Numerical results indicate that the transmission performance of coherent optical systems can be significantly degraded by the EEPN, especially when FF-DBP is used for the nonlinearity compensation. The larger the linewidth of the local oscillator (LO) laser is, the more serious the degradation caused by EEPN is. This deterioration leads to a decrease in optimal launch powers, AIRs and MERs in the long-haul optical communication systems. In the DP-16QAM transmission system, because of the interference of the EEPN generated by the LO laser with a linewidth of 1 MHz, the degradations on the AIR and MER are 0.15 Tbit/s and 4.15 dB in the case of FF-DBP, respectively. It can also be concluded that, for coherent optical systems with long transmission distances and high symbol rates, the compensation bandwidth and the computational complexity of MC-DBP in the DSP module can be significantly reduced by using narrower-linewidth LO lasers

A Renewable and Ultrasensitive Electrochemiluminescence Immunosenor Based on Magnetic RuL@SiO2-Au∼RuL-Ab2 Sandwich-Type Nano-Immunocomplexes

An ultrasensitive and renewable electrochemiluminescence (ECL) immunosensor was developed for the detection of tumor markers by combining a newly designed trace tag and streptavidin-coated magnetic particles (SCMPs). The trace tag (RuL@SiO2-Au∼RuL-Ab2) was prepared by loading Ru(bpy)32+(RuL)-conjuged secondary antibodies (RuL-Ab2) on RuL@SiO2 (RuL-doped SiO2) doped Au (RuL@SiO2-Au). To fabricate the immunosensor, SCMPs were mixed with biotinylated AFP primary antibody (Biotin-Ab1), AFP, and RuL@SiO2-Au∼RuL-Ab2 complexes, then the resulting SCMP/Biotin-Ab1/AFP/RuL@SiO2-Au∼RuL-Ab2 (SBAR) sandwich-type immunocomplexes were absorbed on screen printed carbon electrode (SPCE) for detection. The immunocomplexes can be easily washed away from the surface of the SPCE when the magnetic field was removed, which made the immunosensor reusable. The present immunosensor showed a wide linear range of 0.05–100 ng mL−1 for detecting AFP, with a low detection limit of 0.02 ng mL−1 (defined as S/N = 3). The method takes advantage of three properties of the immunosensor: firstly, the RuL@SiO2-Au∼RuL-Ab2 composite exhibited dual amplification since SiO2 could load large amount of reporter molecules (RuL) for signal amplification. Gold particles could provide a large active surface to load more reporter molecules (RuL-Ab2). Accordingly, through the ECL response of RuL and tripropylamine (TPA), a strong ECL signal was obtained and an amplification analysis of protein interaction was achieved. Secondly, the sensor is renewable because the sandwich-type immunocomplexes can be readily absorbed or removed on the SPCE’s surface in a magnetic field. Thirdly, the SCMP modified probes can perform the rapid separation and purification of signal antibodies in a magnetic field. Thus, the present immunosensor can simultaneously realize separation, enrichment and determination. It showed potential application for the detection of AFP in human sera

Formal verification of safety protocol in train control system

In order to satisfy the safety-critical requirements, the train control system (TCS) often employs a layered safety communication protocol to provide reliable services. However, both description and verification of the safety protocols may be formidable due to the system complexity. In this paper, interface automata (IA) are used to describe the safety service interface behaviors of safety communication protocol. A formal verification method is proposed to describe the safety communication protocols using IA and translate IA model into PROMELA model so that the protocols can be verified by the model checker SPIN. A case study of using this method to describe and verify a safety communication protocol is included. The verification results illustrate that the proposed method is effective to describe the safety protocols and verify deadlocks, livelocks and several mandatory consistency properties. A prototype of safety protocols is also developed based on the presented formally verifying method